\section{Experimental Results}
	
	We used the ETL tool to import a subset of the source data into our warehouse. The speed of the tool was measured as approximately 10000 rows in the source reading table per 5 minutes.
	
	Note that all measurements in this section were done on a machine with a 2.2 GHz Intel Core 2 Duo processor, 2 GBs of 667 MHz DDR2 SDRAM, and a 5400 RPM harddrive with 1.5 Gb/s SATA interface. As one might guess, during the testing of the ETL tool, the harddrive seemed to be the bottleneck, closely followed by the CPU. Since the ETL tool operates on only one source row at a time, memory is no concern at all. Conversely, since nothing is kept in memory, some extra database lookups are needed for every row, leading to more work for the harddrive. This could be optimized for the BagTrack system specifically, by having an ETL server constantly running, accepting readings as they are made, and caching as much of the data, that our prototype looks up, as possible.
	
	We tested the data warehouse with a few analytical questions that might prove useful in a real-world situation. First, in figure \ref{lst:avg_location}, we get the average amount of seconds spent in the different types of locations. We then do a drill-down on the location dimension, in figure \ref{lst:avg_location_airport}, to see the same averages by airport.
	
	\begin{figure}[h!tb]
		\begin{lstlisting}
-----------------------------------
Location Type      Average Duration
-----------------------------------
arrival                    912.0467
check_in                    70.5742
gateway                   1299.0879
sorter                     773.9168
storage                    181.1693
transfer                   682.4249
unknown                    5259.087
-----------------------------------
ALL                         690.349
-----------------------------------
		\end{lstlisting}
		\caption{Average time spent by bags in location types.}
		\label{lst:avg_location}
	\end{figure}
	
	\begin{figure*}[h!tb]
		\begin{lstlisting}
Avg.Dur.       lla     mmx      ls     cph     arn     aal
----------------------------------------------------------
transfer      0.00    0.00    0.00  655.69 1330.58    0.00
gateway       0.00    0.00    0.00    0.00    0.00 1299.09
sorter      436.01    0.00    0.00  736.33    0.00  871.14
check_in    116.49  690.31    0.00    0.00    0.00   33.84
arrival       0.00  115.91    0.00  835.16   23.61 1125.36
unknown       0.00    0.00 5259.09    0.00    0.00    0.00
storage       0.00    0.00    0.00  181.17    0.00    0.00
		\end{lstlisting}
		\caption{Average time spent by bags in location types, per airport.}
		\label{lst:avg_location_airport}
	\end{figure*}
	
	Then, in figure \ref{lst:lost_bags_query}, we test a query to find the amount of bags that have been known to be lost, per airport. Note that this query would not be visible to end-users of the data warehouse -- they would only see the results.
	
	\texttt{NumericStatus} is a MySQL function that simply takes a \texttt{VARCHAR} and returns 1 if the input is 'lost' and 0 if it is 'ok'. This allows us, by finding stays within each airport with a distinct bag, then calculating the sum, to find the amount of lost bags.
	
	\begin{figure}[h!tb]
		\lstset{language=SQL}
		\begin{lstlisting}	
mysql> SELECT d.l_airport, SUM(NumericStatus(d.status)) AS bagslost
    -> FROM
    -> (SELECT DISTINCT l.l_airport, f.bag_ID, f.status
    -> FROM dimension_location l
    -> JOIN fact_stay f
    -> ON l.l_ID = f.location_ID) AS d
    -> GROUP BY d.l_airport;
+-----------+----------+
| l_airport | bagslost |
+-----------+----------+
| aal       |        0 |
| arn       |        4 |
| cph       |        5 |
| lla       |        0 |
| ls        |        1 |
| mmx       |        0 |
+-----------+----------+
6 rows in set (0.31 sec)
		\end{lstlisting}
		\caption{Query to find amount of lost bags per airport.}
		\label{lst:lost_bags_query}
	\end{figure}
	
	Finally, in figure \ref{fig:excel_graph}, we show a graphical representation of output from a query to find the number of bags handled in different airports, grouped by months.
	
	\begin{figure*}[h!tb]
		\includegraphics[width=\textwidth]{parts/images/chartfromexcel.pdf}
		\caption{Graph of query to retrieve number of bags handled in different airports grouped by months.}
		\label{fig:excel_graph}
	\end{figure*}